The Tai or Zhuang–Tai languages ( or , transliteration: or ) are a branch of the Tai–Kadai language family. The Tai languages include the most widely spoken of the Tai–Kadai languages, including standard Thai or Siamese, the national language of Thailand; Lao or Laotian, the national language of Laos; Burma's Shan language; and Zhuang, a major language in the southern Chinese province of Guangxi.